GB2347638A

GB2347638A - Method and apparatus for manufacturing mattress spring units

Info

Publication number: GB2347638A
Application number: GB9905543A
Authority: GB
Inventors: Thomas Patrick Kellett
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-03-11
Filing date: 1999-03-11
Publication date: 2000-09-13
Anticipated expiration: 2019-03-11
Also published as: GB9905543D0; GB2347638B

Abstract

Mattress spring units are manufactured by forming a plurality of spring elements (12) from a roll of high tensile wire. Rows of the spring elements (12) are secured together by lengths of helical wire (15) until the desired size of spring unit is formed. The formed spring unit is transferred to an oven (50) where it is tempered. Following cooling in air the spring units (10) are either formed into a roll or bands (20, 21) are attached to the outer spring elements (10). The oven (50) is a convector oven and is provided with layers of insulation in its side walls (53) and roof (57) so that the heat loss is kept to a minimum.

Description

METHOD OF AND APPARATUS FOR MANUFACTURING MATTRESS SPRING UNITS The present invention relates to a method of, and apparatus for, manufacturing mattress spring units. Each unit forms the spring core of a padded mattress which is normally placed on a bed base to make a complete bed.

The present invention provides a method of manufacturing mattress spring units comprising forming a plurality of spring elements from a roll of high tensile wire, securing a plurality of the spring elements together by lengths of helical wire until the desired size of spring unit is formed, transferring the formed spring unit to an oven, tempering the formed spring unit, cooling the tempered spring units in air and transferring the spring units to a further manufacturing step.

Advantageously, the method includes compressing a plurality of spring units sequentially between rollers in a rolling apparatus, with one or more sheets of material being interposed between each spring unit and forming the compressed spring units into a bale for transport purposes.

Alternatively, the method includes forming two bands from steel wire into a rectangular shape corresponding to the shape of the spring unit, securing the ends of the band together by a mechanical fixing or welding and attaching the steel bands onto the upper and lower edges of the spring elements at the periphery of the spring unit.

Preferably, the method includes tempering the spring units at a temperature in the range of 284-290 C for a period of 10-14 minutes.

Advantageously, the method includes tempering the spring units at a temperature of approximately 287 C for a period of approximately 12 minutes.

Additionally, the method includes heating the oven and spring units for a period of 3 to 6 minutes until the desired tempering temperature is achieved.

Preferably, the oven and spring units are heated for approximately 4 minutes.

The present invention provides an apparatus for manufacturing mattress spring units, comprising means for forming a plurality of spring elements from a roll of high tensile wire, means for securing a plurality of the spring elements together by lengths of helical wire to form the desired size of spring unit, a tempering oven, means for transferring the formed spring units into the oven and for transferring the tempered spring units to a cooling area.

Advantageously, the apparatus includes a rolling apparatus for sequentially compressing a plurality of spring units and means for forming the compressed spring units into a bale for transport purposes.

Preferably, the apparatus includes means for forming rectangular shaped bands from steel wire, means for securing the ends of bands together and means for attaching the steel bands onto the upper and lower edges of the spring elements at the periphery of the spring unit.

Conveniently, the tempering oven comprises a rectangular shaped oven having two elongated side walls and a roof, the side walls being of triple skin construction and the roof being of a double wall construction, with layers of fibre insulation and sand insulation respectively included between the individual skins of the side walls and a layer of sand insulation included between the skins of the roof.

The invention will hereinafter be more particularly described with reference to the accompanying drawings which show, by way of example only, one embodiment of a mattress spring unit manufactured in accordance with the method and apparatus of the invention and an embodiment of an oven used in the manufacture of the mattress spring unit. In the drawings: Figure 1 is a perspective view of the mattress spring unit; Figure 2 is a plan view on a larger scale of one corner of the mattress spring unit; Figure 3 is a perspective view of a mid portion of the mattress spring unit; Figure 4 is a perspective view of one spring element, a plurality of which comprise the main structure of the spring unit; Figure 5 is a perspective view of an oven forming part of the apparatus of the invention and Figure 6 is a cross sectional view through the oven of Figure 5 showing one of the mattress spring units.

Referring to the drawings, the mattress spring unit 10 comprises a large number of Bonnell inner spring elements 12 which are secured together at their upper and lower ends 13,14 by parallel lengths of helical wire 15. The unit 10 is surrounded by bands 20,21 at its upper and lower ends respectively attached to each spring 12 at the edge of the unit by means of clips 25.

To manufacture the mattress spring unit 10, the inner spring elements are first manufactured from 2.18 mm or 2.39 mm high tensile carbon steel wire which is taken off from 1 tonne reels, by a spring coiling machine. To form a spring, the coiling machine forms a"five turn spring"with the ends 13 and 14 being the large diameter turns with the both ends of the high tensile carbon steel wire formed into knots 16 and 17 to secure the wire ends. The spring elements 12 are secured together at their top and bottom ends 13,14 by lengths of 1.32 mm helical wire.

The number of spring elements 12 comprising the unit will depend on the width of the spring 10 unit, e. g. 0.9 m (3 feet), 1.35 m (4.5 feet), 1.5m (5 feet) or others for the size of the eventual bed which is to be manufactured.

The completed spring units 10 are placed on an overhead hanger which transports the spring units 10 to the oven 50 in which the springs are tempered.

The oven 50 which is shown in Figures 5 and 6 is a convector oven into which a batch of spring units 10 are loaded and the doors of the oven closed. The oven 50 has a double skin roof 52 and triple skin side walls 53. Between the outer skins 54 and middle skins 55 of each of the side walls 53 is a layer of fibre insulation 56. Between the middle skins 55 and inner skins 57 of each of the side walls 53 is a layer of sand insulation 58. Finally, between the outer skin 60 and inner skin 61 of the roof 52 is a layer of sand insulation 62.

All of these layers of insulation ensure that heat loss from the oven is kept at a minimum.

When the oven has been filled with the batch of spring units 10 and sealed, the oven takes approximately 4 minutes to achieve the desired temperature of 287 C after which the units are maintained at that temperature for twelve minutes. The units are then removed from the oven and allowed to air cool back to ambient temperature. During the tempering process, the overall height of the spring elements is reduced from 146 mm (5.75 inches) to 140 mm (5.5 inches) and the lubricating liquid of teflon and paraffin oil, necessary for the formation of the springs, is burned off without causing any harmful odours or vapours.

Depending on where the spring units are finally assembled, the process now divides into two streams. In one stream up to ten tempered units are rolled into a cylindrical bale, by a large rolling press and secured so as to form a readily transportable pack for transport to a factory finishing the spring unit manufacturing process or producing mattresses.

In the other stream, the next step in the process is the forming of the bands 20 and 21 by bending and forming two lengths of 4mm border wire into two equal sized rectangles. The ends of wire are secured together by a ferrule 30 which is pressed about and secured to the two adjoining ends. The bands 20 and 21 are then clipped to the outer spring elements 10 by clips 25.

The completed spring unit can then be transferred to a section or a plant manufacturing mattresses.

It is to be understood that the invention is not limited to the specific details described above which are given by way of example only and that various modifications and alterations are possible without departing from the invention as defined in the appended claims.

Claims

CLAIMS 1. A method of manufacturing mattress spring units comprising forming a plurality of spring elements from a roll of high tensile wire, securing a plurality of the spring elements together by lengths of helical wire until the desired size of spring unit is formed, transferring the formed spring unit to an oven, tempering the formed spring unit, cooling the tempered spring units in air and transferring the spring units to a further manufacturing step.
2. A method of manufacturing mattress spring units as claimed in Claim 1, including compressing a. plurality of spring units sequentially between rollers in a rolling apparatus, with one or more sheets of material being interposed between each spring unit and forming the compressed spring units into a bale for transport purposes.
3. A method of manufacturing mattress spring units as claimed in Claim 1, including forming two bands from steel wire into a rectangular shape corresponding to the shape of the spring unit, securing the ends of the band together by a mechanical fixing or welding and attaching the steel bands onto the upper and lower edges of the spring elements at the periphery of the spring unit.
4. A method of manufacturing mattress spring units according to any one of the preceding claims, including tempering the spring units at a temperature in the range of 284 290 C for a period of 10-14 minutes.
5. A method of manufacturing mattress spring units according to Claim 4, including tempering the spring units at a temperature of approximately 287 C for a period of approximately 12 minutes.
6. A method of manufacturing mattress spring units according to Claim 4 or Claim 5, including heating the oven and spring units for a period of 3 to 6 minutes until the desired tempering temperature is achieved.
7. A method of manufacturing mattress spring units according to Claim 6, including heating the oven and spring units for approximately 4 minutes.
8. Apparatus for manufacturing mattress spring units, comprising means for forming a plurality of spring elements from a roll of high tensile wire, means for securing a plurality of the spring elements together by lengths of helical wire to form the desired size of spring unit, a tempering oven, means for transferring the formed spring units into the oven and for transferring the tempered spring units to a cooling area.
9. Apparatus for manufacturing mattress spring units according to Claim 8, including a rolling apparatus for sequentially compressing a plurality of spring units and means for forming the compressed spring units into a bale for transport purposes.
10. Apparatus for manufacturing mattress spring units according to Claim 8, including means for forming rectangular shaped bands from steel wire, means for securing the ends of bands together and means for attaching the steel bands onto the upper and lower edges of the spring elements at the periphery of the spring unit.
11. Apparatus for manufacturing mattress spring units according to any one of the preceding claims, in which the tempering oven comprises a rectangular shaped oven having two elongated side walls and a roof, the side walls being of triple skin construction and the roof being of a double wall construction, with layers of fibre insulation and sand insulation respectively included between the individual skins of the side walls and a layer of sand insulation included between the skins of the roof.
12. A method of manufacturing mattress spring units substantially as herein described with reference to the accompanying drawings.
13. Apparatus for manufacturing mattress spring units substantially as herein described, with reference to, and as shown in Figures 5 and 6 of the accompanying drawings.
14. Mattress spring units whenever manufactured in accordance with the method as claimed in any one of Claims 1 to 7 and 12 or using the apparatus as claimed in any one of claims 8 to 11 and 13.